JP2000024679A - Treating device of high concentration sewage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a treating device of a high concn. sewage capable of removing nitrogen and SS in raw water and moreover, easy in regeneration by washing of a filter medium. SOLUTION: In a circulation type nitrification/denitrification device in which a denitrification tank 1 and a nitrification tank 2 are arranged side by side, treated water in the denitrification tank 1 is supplied to the nitrification tank 2 and a part of the treated water in the nitrification tank 2 is returned to the denitrification tank 1, a filter medium layer is formed in the tank by using a floatable filter medium piece made of a synthetic resin-made fiber as a filter medium 3 to be packed in the nitrification tank 2 and an air diffusing pipe 8a for washing is disposed under the filter medium layer. The filter medium 3 is large in a contact area with the sewage, high in strength and good in water permeability, suitable for the sewage treatment and also easy in regeneration by washing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for treating organic sewage such as sewage.

[0002]

2. Description of the Related Art Conventionally, apparatuses for treating organic wastewater are known. A nitrification apparatus using a filter medium such as anthracite or ceramic having a specific gravity of 1.0 or more is well known. In addition, there are many nitrification apparatuses using a buoyant filter medium having a specific gravity close to 1, and the shape and dimensions of the filter medium used in these apparatuses are 5 to 25 mm in a rectangular parallelepiped 10 to 30 mm square.
Are known. These filter media dimensions are larger than filter media such as anthracite and ceramic. This is considered to prevent clogging of the filter layer.However, if the filter medium size is too large, the filtration resistance is not uniform, and a large amount of water to be treated flows into a low resistance portion, so-called a drift phenomenon, and the treatment is difficult. This results in trouble. Furthermore, there are many filter media called fiber filter media in which synthetic fibers are bundled or formed into a cocoon shape. Many of these are made of one type of fiber, which may increase the filtration resistance or may be deformed by being strongly pressed by gravity during drainage. Also,
In the upward flow filtration, raw water and air flow in the same direction,
There is a disadvantage that S easily leaks into the treated water.

[0003]

However, in a high-load processing apparatus using a buoyant filter medium having a specific gravity close to 1, the filtering speed is low, so that the pressure density of the filter medium is not sufficient, and air rising in the layer is not sufficient. At the same time, SS may escape into the treated water. In the case of anthracite or ceramic filter media with a large specific gravity, or foamable filter media with an extremely small specific gravity,
Porosity is small, clogging by SS occurs in a short time, cleaning frequency increases, and large power is required for cleaning.
Then, the complicated washing of the nitrification tank causes nitrifying bacteria having a low growth rate to flow out. Furthermore, a large-sized filter medium causes a drift phenomenon, which hinders processing.

[0004]

According to the present invention, a filter medium to be charged into a nitrification tank is devised, an appropriate ratio between a filter medium layer height and a water layer height is provided, and a part of filtered water is circulated. By doing so, a filter medium layer is formed that is hardly clogged and easy to backwash while capturing even fine SS. That is, the core material is polypropylene as the filter medium,
A heat-fusible conjugate fiber made of polyethylene and having a fineness of 18
A first filament having a denier of 65 to 65 denier; a second filament having a denier of 3 to 10 denier made of polypropylene fiber; and a heat-fusible composite fiber having a core of polypropylene and a sheath of polyethylene having a denier of 1. A web mixed with a third filament having a denier of 5 to 6 is formed into a cloth by a needle punching method, and is heated without smoothing the state of raising the web on both sides. 2-8
mm of a cloth-shaped plate, and the cloth-shaped plate is 3 to 3 mm.
The material cut into 5 mm squares was used as a filter medium. Further, the ratio between the height of the filter medium layer and the height of the water layer is set to 65:35 to 5
By setting the ratio to 0:50, washing of the filter medium is facilitated, and furthermore, the disadvantage that the SS escapes into the treated water together with air due to insufficient consolidation of the filter medium is solved by increasing the pressure density by circulating the treated water. is there.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The above-mentioned cloth-shaped plate-shaped filter medium is a non-woven fabric, so that it has a high porosity and is excellent in adhering microorganisms. Therefore, the amount of microorganisms in the filter layer can be kept large. In addition, three types of filaments having different thicknesses are used in order to prevent crushing due to gravity at the time of filtration pressure or drainage. The cloth-shaped plate-shaped filter medium is densely packed but has a high porosity, so that pressure loss due to clogging is small and filtration time is long. In the washing, by setting the ratio of the filter medium layer height to the water layer height to 65:35 to 50:50, it is easy to flow by diffused air from below, and the trapped SS and excess sludge can be separated. At this time, the amount of air is smaller than that of an anthracite or ceramic filter medium device. Further, the SS leakage, which is a drawback of the upward flow type, is solved by circulating the treated water, and the treated water having a lower SS than before can be obtained. Further, since the circulated water mixes the treated water in which oxygen is sufficiently dissolved into the raw water, the amount of aerated air may be smaller than that of the conventional apparatus. Hereinafter, a sewage treatment apparatus using a filter medium according to the present invention will be described with reference to the drawings.

[0006]

FIG. 1 shows a processing apparatus according to the present invention, which will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a denitrification tank in which the lower part is formed in an inverted cone shape and a settling portion is provided, 2 denotes a nitrification tank in which the lower portion is formed in an inverted cone shape and a settlement portion is provided, 3 denotes a denitrification tank and A filter medium charged in the nitrification tank, 4 is a supply pipe for raw water, 5 is a pipe for taking out treated water, 6 is a circulation path for circulating a part of the nitrification treated water to the denitrification tank, 6a is a pump for circulation, 7 Is a pipe for supplying denitrification water to the nitrification tank 2, 8 is a supply pipe for cleaning air, 8a is a diffuser pipe for cleaning, 8b is a diffuser pipe for aeration, and 9 is a nitrification circulator for circulating a part of the nitrification water. Route,
9a is a circulation pump.

[0007] Since the apparatus according to the present invention is configured as described above, raw water is mixed with the nitrification-treated water from the nitrification tank 2 and supplied to the denitrification tank 1. The mixed water supplied to the denitrification tank 1 rises in the filter medium layer to capture and remove fine SS, and at the same time, touches the anaerobic microorganisms inhabiting the filter medium 3 to denitrify the nitrification liquid, Organic pollutants are anaerobically decomposed and supplied to the nitrification tank 2 through the upper part of the denitrification tank 1. In the nitrification tank 2, ascending in the filter medium layer, mainly ammoniacal nitrogen in the raw water becomes nitric acid by the action of nitrifying bacteria, a part of which is taken out as treated water, and the rest is mixed with the raw water to be denitrified in the denitrification tank 1. It is circulated and partly circulated to the nitrification tank inlet.

[0008] During such a treatment operation, the filter medium 3 according to the present invention is a synthetic resin fiber filter medium, so that it has a large contact area, can efficiently decompose pollutants in wastewater, and has strength. Therefore, the eyes are not crushed by the raw water pressure, and the eyes are hardly clogged, and long-time operation is possible.

Next, by performing such an operation, the filter medium layer becomes S
When clogging is caused by sludge or the like generated during decomposition of S and organic substances or during denitrification or nitrification, the supply liquids are stopped, and washing is performed individually. That is, the filter medium layer is loosened and stirred with the air from the supply pipe 8, and at the same time, the washing water is sent to discharge the SS separated from the filter medium 3 out of the tank. Then, after the discharge is completed, raw water is supplied to restart the operation. Also in the washing operation of the filter medium 3, since the filter medium 3 of the present invention is a synthetic resin fiber filter medium, it has good water permeability, is easy to loosen, and has strength, so that it is not worn by stirring.

Further, in stirring the filter medium 3, a draft tube 1a, which is provided upright at the center of the processing tanks 1, 2,
Numeral 2a guides the air from the cleaning air diffuser 8a provided in the lower opening to form a vertical circulating flow of the cleaning water in the tank so that the filter medium 3 can be efficiently stirred and cleaned.
Further, the ratio of the height of the filter medium layer to the height of the water layer is set to 65:35 to 50: 5.
The reason why the ratio is set to 0 is that the ratio has found the ratio between the amount of the filter medium and the amount of water that allows the filter medium 3 to be stirred and flow most efficiently during the above-described filter medium stirring and washing.

[0011]

As described above, according to the present invention, in a sewage nitrifying apparatus using a filter medium made of synthetic resin fiber material,
The treated water section and the inflow section are connected via a circulation pump to circulate part of the treated water, and the ratio between the height of the filter medium layer and the height of the water layer is charged so as to be appropriate for stirring. SS and organic pollutants can be separated and removed in a single tank. In particular, the formation of the filter layer is stabilized by circulation, the dissolved oxygen in the treated water can be reused, and the advanced nitrification of the wastewater becomes possible. This makes it possible to reduce the amount of waste and to completely wash the filter medium.

[Brief description of the drawings]

FIG. 1 is a system diagram of a high-concentration sewage treatment apparatus according to the present invention.

FIG. 2 is a perspective view of a filter medium used in the high-concentration sewage treatment apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Denitrification tank 2 Nitrification tank 3 Filter medium 8a Cleaning diffuser 9a Circulation pump

Claims (4)

[Claims] 1. A denitrification tank 1 and a nitrification tank 2 are arranged in parallel.
Is supplied to the nitrification tank 2 and a filter medium 3 charged into the nitrification tank 2 is made of synthetic resin in a circulating nitrification denitrification apparatus in which the treated water of the nitrification tank 2 is returned to the denitrification tank 1. An apparatus for treating high-concentration sewage, in which a filtration layer is formed in a tank as a buoyant filter medium piece made of a fiber material made of stainless steel, and a diffuser 8a for washing is disposed below the filtration layer. 2. A first filament having a denier of 18 to 65 denier, a heat-fusible conjugate fiber having a core of polypropylene and a sheath of polyethylene, and a material of polypropylene, wherein the material of the filter medium 3 charged into the nitrification tank 2 is polypropylene. Fiber with fineness of 3-10
A web formed by mixing a denier second filament and a heat-fusible conjugate fiber having a core of polypropylene and a sheath of polyethylene and a third filament having a fineness of 1.5 to 6 denier is needle-punched. And heat-treated without smoothing the web raised state on both sides to produce a cloth-shaped plate-like body having a weight of 200 to 800 g / m 2 and a thickness of 2 to 8 mm,
2. The high-concentration sewage treatment apparatus according to claim 1, wherein the cloth-shaped plate-like body cut into a 3 to 5 mm square is loaded as a filter medium. 3. The cloth-shaped plate-shaped filter medium is charged so that the ratio of the filter medium layer height to the water layer height of the filter medium 3 charged in the nitrification tank 2 is 65:35 to 50:50. The high-concentration sewage treatment apparatus according to claim 1 or 2, characterized in that: 4. A treatment water section of the nitrification tank 2 and a treatment water inflow section of the denitrification tank 1 are connected via a circulation pump 9a so that a part of the treatment water is circulated at a linear velocity of 5 to 20 m / h. The high-concentration sewage treatment apparatus according to claim 1, wherein: